Character reading system

ABSTRACT

909,943. Automatic character reading. NATIONAL CASH REGISTER CO. Oct. 11, 1960 [Dec. 23, 1959], No. 12581/62. Divided out of 909,942. Class 106 (1). [Also in Group XXXIX] Clock pulses used for sampling signals derived from sensing a character as described in Specification 909,942 are synchronized with a trigger signal by being variably delayed in a circuit having first and second variable delay circuits into one of which is set a delay so that the clock pulses are delayed by the time interval between the leading edge of a clock pulse and the trigger signal. The variable delay circuit is as described in Specification 907,492 and consists of a magnetic core 1, Fig. 1, having an approximately square hysteresis characteristic and two openings 2 and 3. The winding 5 &#34; resets &#34; the core by establishing, say, an anticlockwise flux when a pulse is applied to terminal R. Winding 4 sets the core by removing part of the reset magnetism by a contrary flux, the proportion removed being dependent upon the length of the pulse applied to terminal S. The flux is now as shown by the arrows in the neighbourhood of the opening 3. This flux is reversed by energization of a winding 6 by current from 50 volts source through transistor 11 when a clock pulse V1 is applied at terminal 12. The other end 13 of the winding 6 is connected through a diode to the 4-volt source and through a resistor to the 50- volts source. When the positive pulse V1 is first applied to terminal 12 the impedance of the coil 6 is high because of the flux reversal around the opening 3. This keeps up the potential of the end connected to the 50-volts source and causes terminal 13 to remain at 4 volts. When the flux is fully reversed, the impedance falls and the coil 6 becomes substantially a shortcircuit so that the potential at terminal 13 falls to zero as shown at V 0  in Fig. 2. At the end of the clock pulse V1 the transistor 11 cuts off de-energizing winding 6 and allowing permanently energized winding 7 to start resetting the flux round opening 3. This gives rise to a positive pulse V2 which is connected to cause transistor 14 to conduct and hold point 13 to zero potential. At the end of the resetting period the transistor 14 cuts off and the point 13 returns to 4 volts as shown at V 0 , Fig. 2. Both the leading and trailing edges are therefore delayed by the variable period. In the complete circuit, Fig. 3, the clock pulses C are amplified and applied to gates 18 and 19 in inverted and true forms respectively. The triggering pulse is applied to a flip-flop G the &#34; 0 &#34; output of which is applied to both gates, and the &#34; 1 &#34; output to gates 21, 22. Normally, with the flip-flop G unset, the clock pulses C are applied through gate 19 to the reset terminal R of delay circuit XI and the set terminal S of X 2. The inverted clock pulses C&lt;SP&gt;1&lt;/SP&gt; through gate 18 to the set terminal S of delay circuit XI and the reset terminal R of X2. Normally the cores of the delay circuits are reset and set alternately the two circuits working in anti-phase. The gates 18, 19 close when the trigger pulse sets flip-flop G so that whichever circuit is being set the setting process is cut short. The delay interval is arranged to equal the period during which setting has taken place. The clock pulses at C are delayed by that amount in the set circuit. Flip-flop Q is set or reset by the outputs of the gates 18, 19 to open one of the gates 21, 22 to pass the delayed clock pulses from the appropriate circuit. A third input to these gates is from flip-flop G to ensure that clock pulses are transmitted only after a trigger pulse has been received.

Sept. 3, 1963 r. c. ABBOTT, JR., ETAL CHARACTER READING SYSTEM 7Sheets-Sheet l Filed Deo. 23, 1959 .162 I n i 1.5.5 164 156\`/\Q Sept.3, 1963 T. c. ABBOTT, JR.. ETAL 3,102,995

CHARACTER READING SYSTEM Filed Dec. 23, 1959 7 Sheets-Sheet 2 2 Ca/umnfa# e #f of [46 mvg@ @LLESBQHL.' ffbwam; 35 uw 1', Y 3 I 132 i 133 F. .5%l l I I 196' 200 Sept- 3 1963 T. c. ABBOTT, JR., ETAL 3,102,995

CHARACTER READING SYSTEM '7 Sheets-Sheet 3 Filed Dec. 23, 1959 RuG Naiumh UQ@ Nn QM Sept. 3, 1963 T. c. ABBOTT, JR., ETAL 3,102,995

CHARACTER READING SYSTEM Filed Dec. 25, 1959 7 Sheets-Sheet 4 rxwVl/ x I1 [l/Pez/Ifa/f I *rt l l- Laafr/ Vea/fdl 0 www 05251 J f V 0 00101 ffgzz Sept. 3, 1963 T. c. ABBOTT, JR.. ETAL 3,102,995

CHARACTER READING SYSTEM Filed Dec. 25, 1959 7 Sheets-Sheet 5 Sept. 3,1963 T. c. ABBOTT, JR.. ETAL 3,102,995

CHARACTER READING SYSTEM Filed Dec. 23, 1959 7 Sheets-Sheet 6 pig? T-.dw

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Sept 3, 1963 T. c. ABBOTT, JR., ETAL 3,102,995

CHARACTER READING SYSTEM 'T Sheets-Sheet 'T Filed Dec. 23, 1959 kuvwUnited States Patent O CHARACTE 3102995 R READING SYSTEM T11-ey C.Abbott, Jr., Los Angeles, and Herbert L. Bernstein, Inglewood, Calif.,assignors to The National Cash I`RlgrisitztlgdCompany, Dayton, Ohio, acorporation of Filed Dec. 23, 1959, Ser. To. 861,469 20 Claims. (Cl.S40-146.3)

b n c, equipment in usxness practice as is possible to perform therequired functions Thus, although magnetic detecting systems have attimes been suggested in the ing equipment can be employed, with the usedto form the characters being in most major change requirement. ioreover,in business systems where documents are not handled generally by thepublic, the main advantage attributed to magnetic systems, which is thatreliable reading of the printing is not affected by overstamping, is ofminor importance because of the internal control that can be made inmany business establishments in this respect.

In view of the above, it appears that the approach of reading charactersas inked and printed by conventional equipment is highly desirable andworth pursuing, but kto accomplish this, other factors must beconsidered and overcome such as the necessity of providing opticalreadstyle of type instances the recognized and distinguished by thehuman eye. Furthermore, the paper conventionally used for printedinformation in the day-by-day business practice may have defectstherein, such as foreign matter, which although of no consequence andvirtually unnoticeable to the human eye, may be intolerable whenreliable reading by automatic equipment is desired.

Thus, in the printing of characters, by conventional wheel-type printingequipment for example, such as employed in cash register and otherwidely used devices of a similar nature, mjsregistration or variation inthe spatial relation of one character with respect to other charactersin a row, or relative to a normal position in a row, is likely to occur;or the character may be slightly skewed or tilted from its normalposition. In such equipment, thc misregistration or difference indisplacement between the highest and lowest character printed in a lineor row may in an extreme instance be as great as twenty percent of thecharacter height. The spacing of the characters along the line normallyis held to closer tolerances but may vary depending upon the printingmechanism. Furthermore, in such equipment, it is possible to havevariations in weight or uniformity of the lines forming `the print,i.e., the print may be lighter or darker or the Width of the linedefining the character may vary, or the line may be spattered, due, forexample, to the use of freshly inked ribbons. This type of variationcompounds the difficulties encountered in character misregistration inmaking it more difficult to 3,102,995 Patented Sept. 3, 1963 determinethe exact relative position of character line segments used in formingthe over-al1 character.

As for the optical scanning of characters printed on ordinary stockquality of paper, the dimculty presented is that the paper may, due tospot variations in shading, appear non-uniform to the optical detector;or foreign particles in the paper stock may be erroneously considered asuseful information or at least introduce appreciable noise into thesystem, thus interfering with the reliable reading of the characterprinted thereon.

The present invention overcomes the foregoing dithculties in readingcharacters printed on stock quality paper with conventional inking andprinting equipment by providing novel circuitry and apparatus in anoptical reading system which detects the location of a scanning deviceover predesignated portions of each of the characters in a row of print,for example, so that the character can be reliably read even thoughthere are misregistrations or other variations in the print of theindividual characters in the row. Furthermore, the present invention andapproach provides a means and arrangement for scanning characters whichpermits a sufficiently large size scanning aperture to be employed suchthat, even if imperfections are optically detected in the paper, forexample, the signal resulting from such imperfections is such a smallpercentage of the total spot being viewed by the scanner at any onetime, that the noise introduced in the output signal is negligible.

Briefly, the present invention provides for reading characters whichhave been stylized such that when the character, as normally viewed, isdivided into a plurality of vertical zones, segments of the linesforming the character appear in selected ones of, for example, the upperand lower halves of the vertical zones. These characters are printed intransverse rows on a tape, for example. A scanning device is providedfor progressively scanning a row of characters, as the tape is moved.The movement of the scan across a row of characters is synchronized witha timing means whose outputs define the position of the scan along thevertical zones of the respective characters in a row. As the scanning ofthe row progresses, a record is maintained of the number of times thepresence of each character is detected by the successive scans. Eachtime a character has been detected a predetermined number of times, thescanning device is positioned to scan across the upper and lower halvesof the character. As the scan proceeds to read the churacter, the timingmeans is resynchronized for identifying the movement of the scan as itpasses over the vertical zones of the character. The output waveformsprovided by the scanning device have signals located in positionsthereof identified by the timing means. These signals correspond to thelocations of the line segments in the upper and lower halves of thevertical zones of the respective characters read.

It is an object of the present invention to provide an automaticcharacter reading system having the foregoing features and advantages.

Another object of the present invention is to provide a system forreading a character by first locating a sensing means over a desiredposition of the character by counting the number of times progressivescans by the sensing means sense the presence of the character, and thenreading out the signals sensed when the sensing means scans over thedesired position of the character.

A further object is the provision of a system for reading a line or yrowof characters on a tape which system provides for synchronizing theoutputs of timing circuits with the location of the scan along the rowof characters by initiating or resetting the operation of the timingcrcuits in accordance with signals provided by sensing marks inpredetermined areas of the tape.

Another object of the present invention is the provision of a systemwhich `is capable of reliably reading characters that have been printedby priming equipment having a relatively large permissible tolerance inthe horizontal, vertical and skew misregistration of the printedcharacters relative to each other.

Another object of the invention is the provision of a system for readingprinted characters wherein the weight or width of the line used inprinting the character is permitted to vary.

A further object is to provide a character reading system which providesfor obtaining information which defines a character printed on anordinary stock quality of paper tape by scanning the character aplurality of times with a scanning detector whose sensing area is largerelative to the size of spurious marks or defects that may be present inthe paper.

Another object of this invention provides for reading characters whichhave been stylized Such that the sensing of the position of the linesegments forming the character, as obtained by simultaneous scanning ofthe upper and lower halves of the character, distinguish it from othercharacters in a group.

These and other objects and features of the invention will becomeapparent to those skilled in the art as disclosure is made in thefollowing detailed description of a preferred embodiment of theinvention illustrated in the accompanying sheets of drawings, in which:

FIG. l is a block diagram of a preferred embodiment of the invention;

FIG. 2 illustrates a section of a typical paper tape providing a reco-rdmedium for printed characters to be read by the preferred embodiment ofthe invention;

FIG. 3 shows a section of the paper tape illustrated in FIG. 2 which hasbeen considerably enlarged to facilitate the description of theinvention;

FIG. 4 shows the typical forms of characters read by the preferredembodiment of the invention;

FIGS. 5a, 5b and 5c illustrate typical character lines and correspondingwaveforms of signals produced during the operation of the preferredembodiment of the invention;

FIG. 5a is a block diagram of a peak detector',

FIG. 6 shows the subdivision of the area in which informationrepresenting a typical character is printed;

FIG. 7 shows a circuit diagram of the memory for the scan counter;

FIG. B is a block diagram of the clock setting circuit;

FIG. 8a illustrates certain typical signal waveforms for the circuitshown in FIG. 8;

FIG. 9 is a circuit diagram of a delay circuit used in the clock settingcircuit;

FIG. 10 is a table used for explaining the mechanization of the triggerinputs of the character scan counter;

FIG. `1l is a combined schematic and circuit diagram of the characterscan counter employed in the preferred embodiment of the presentinvention; and

FIG. 11a is a set of typical signal waveforms applied on a logic core ofFIG. l1.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views,there is shown in FIG. l, which illustrates a preferred embodiment, acharacter reader including an optical detector 10 for scanning a tape 12mounted for movement on a tape transport 14. As shown, a drive capstan11 of the tape transport is coupled to a synchronous motor 13 to movethe tape at a desired speed past the face of a forming head 19, whichface defines the scanning station 17 for the tape.

An image of the section of the tape at the scanning station is formed byan optical lens 28 on the outer periphery of a rotating drum 20 includedin the detector 10. In order that the image will be in focus for theentire length of a row of characters extending across the width of thetape, the curved face of the forming head 19 is made to conform to thecurvature of the drum periphery, and the section of the tape at thescanning station 17 is maintained against the curved face of the forminghead 19 by perforations leading to a vacuum chamber provided in thehead.

The periphery of the rotating drum 2() is provided with four pairs ofapertures, each pair designated 221? and 22b. The pairs of apertures areequally spaced about the drum periphery. The section of the periphery ofthe drum opposite the scanning station 17 is disposed to rotate past aviewing slot or window 23 provided in a stationary shroud 24 surroundingthe drum. Two beam guides 26t and 26b, formed of Lucite rods, forexample, are positioned adjacent the inner peripheral surface of thedrum opposite the window 23 in the shroud. Changes in light level,produced as the image of a row of characters projected from the scanningstation of the tape 12 is scanned by a pair of the moving apertures 22!and 22b, are transmitted through the respective beam guides 2Gb and 261.As shown, the alignment of the drum 2t] provides for movement of thepairs of apertures 221 and 22b in a direction which is 'perpendicular tothe movement of the tape 12 past the scanning station 17. Thus, duringoperation, each pair of apertures of the optical detector 10 providesfor simultaneous scanning of two laterally spaced sections of the imageprojected from the tape. It should be understood that the slot or window23 in the shroud 24 covering the periphery of drum 20 is of such a sizethat the sides of the slot block light projected from the upper andlower edge portions of the tape 12, as viewed in FIG. 2, while passing aband of projected light which is adequate to transmit onto the drumperiphery an image of at least one complete row of the printedcharacters on the tape.

The changes in intensity of the light entering the beam guides 26: and2Gb, as the scanning progresses, are transmitted to respectivephotosensitive elements 301 and 30h. The photosensitive elements 302*and 30h are responsive to light variations to produce respectiveelectrical signal outputs Tj and B1 which are fed into peak detectorcircuits 32. 'These circuits 32 produce shaped signals on outputs T andB, which signals precisely determine in time the centerline of lines ormarks of the tape character images scanned by the optical detector 10.

The signals on each output T and B are produced in response toprogressively scanning images of the character areas along the row ofthe tape. Each of these character areas is defined as a column of thetape. In order to assimilate the information on the outputs T and B ofthe optical detector 10, it is necessary to define the operatingposition of the scan, i.e., the distance of travel of a pair of themoving apertures 22b and 22t, across the columns comprising a row of thetape, with respect to a reference mark provided for each row. This isaccomplished by timing circuits comprising a subcolumn counter 68 and acolumn counter 80, which counters effectively count clock or timingsignals provided for the system. The outputs of the counters define thetime position of the scan in the columns along the row on the tape.

In FIG. l, the source of timing signals is shown to be a disc 36 mountedon a common drive shaft 35 with the drum 20. In a suitable arrangement,as shown, the clock signals are magnetically recorded on a track 33located on the periphery of the disc 36 whereby a read head 37, locatedadjacent to the periphery of the rotating disc, is capable of. detectingand reproducing the clock signals recorded on the track. The clocksignals are coupled from the output of the read head 37 by way of aclock setting circuit 60 and an and gate 66 to the subcolumn counter 68.The disc 36 and drum 20 are driven by a synchronized motor 40 or similarconstant speed motive driver. mechanically linked to the drive shaft 35.The linear' speeds of the periphery of the apertured drum Ztl, timingdisc 36, and tape 12 are adjusted to provide the desired scanning ratefor the detector lll.

Referring next to FIG. 2, a section of the tape 12 is shown havingcharacters which are typical of characters read by the apparatus of thepreferred embodiment. The characters are shown printed in rows acrossthe tape, each row being divided into character areas or columns #l to#3, inclusive. A first row 44 is typical of a complete row of charactersin which no misregistration of characters is visibly noticeable and eachcharacter area or column is occupied by a character. It should be notedthat a vertical line or reference mark 46 is located to the right of thecharacters in the roW, ie., adjacent the least signicant character areaor column #1. Preferably, the reference mark 46 extends vertically aboveand below the highest and lowest portions of the characters in the rowso that during scanning, the optical detector will detect the referencemark prior to detection of a line or mark of any character in the row asthe detector scans from right to left across the tape. ri`he referencemark 46 is always to the right of all of the columns or character areasin a row regardless of absence or `presence or" characters in characterareas. A second row 48 on the tape l2, shown in FIG. 2, illustrates agroup of characters having one character "4" misaligned vertically. Thevertical misalignrnent of the character 4 is a typical misregistrationwhich may occur as a result of misalignment of the character type duringthe ordinary process of setting up the type when printing the tape. Asection of the tape including the characters 4, 2, and the referencemark 46 has been enlarged and shown in a separate view in FIG. 3, inorder to illustrate further details of the preferred embodiment.Reference to FIG. 3 will be made in the ensuing description. A third row52 of the tape shown in FlG. 2 illustrates misalignrnent in printing ofa row of characters in the horizontal or transverse direction across thetape. Note here. that during printing the entire row of charA actersincluding the reference mark 46 had been shifted to the left. ln actualpractice, such a horizontal misregistration might not be so noticeablesince it would be more apt to occur in a gradual manner and couldresult, for example, from a gradual slippage or movement of the tape tothe right in the printer. A following row S4 on the tape illustrates aseries of characters across the tape in which the least signilicantcharacter area or column adjacent the reference mark 46 is unoccupied.lt should be noted here, that the reference mark 46 retains its positionin the row even though the adjacent character area is unoccupied inorder that the column count will not be changed for the remainingcharacters in the row.

Referring back to FIG. l, the timing circuits for defining the charactercolumns of the tape will now be further described. Clock setting circuit60 is provided for setting the clock signals, as received `from readhead 37, into phase with, for example, a reference signal TR obtained byscanning the reference mark 46 provided at the beginning of each rowbeing scanned. As will be explained in detail later in connection withFIGS. S, 8a, and 9, this setting of the clock signal is accomplished bydelaying the leading edge of the rst clock signal C by a fixed period oftime such that it will coincide with the leading edge of the outputsignal TR produced by the reference mark 46. The clock setting circuit6E) operates after each such setting to delay all the following clocksignals by a similar tixed period of time. Setting, i.e., delaying ofthe clock signals in this Way, enables the subcolumn counter 68 andcolumn counter 80 to locate the spatial area of the subcolumns andcolumns on the tape accurately, with respect to the row reference mark46.

The setting circuit 6l) is initially set to properly delay and gate outthe clock signals in response to the triggering of the flip-flop G1 intothe true state by output signal Llll TP, produced by optical detector 10scanning the reference niark 46. The output signal TR is selected fromother signals on output T by an and gating circuit 70, which responds tosignal TR, and an initial reset signal KH produced at the output ofcolumn counter 80. The output of the and gate 7l) is coupled to the truetrigger input g1 of the flip-hop G1 via an or gate 74. As stated,setting of the iiipdiop G1 into a true state initiates the cloclrsetting circuit (it) to delay the clock signals C so as to generateclock signals Cb. which coincide in phase with the output signal TRgenerated at the beginning of a scan of a row of characters.

The subcolumn counter 63 is responsive to clock signais Cs to countthrough a cycle of 18 clock periods, which periods P1 to Pls, inclusive,divide the area allotted to a column on the tape (see FIG. 3). Thesubcolumn counter 6s, thus, counts 18 clock signals Cs receivcd at itsinput to complete a cycle; and the next clock signal C5 serves to resetthe subcolumn counter to P1 to begin a new cycle. The subcolurnn counter68 is provided with individual outputs P1, PU, PV, PW, PX, PY, P17, andP18, which outputs have signals thereon only when the counter actuallyresides in the count indicated thereby.

ln lilG. 3, showing a portion of tape 12, the printing arcacorresponding to each column of the tape is shown divided intotransverse zones including U, V, W, X, and Y. The Width of cach of thesezones with respect to time is equal to three clock periods. For example,zone U corresponds to P counts P2, P3, and P4. Thus, the individualsignal outputs PU, PV, PW, PX, and PY of the subcolumn counter 63correspond to and define the spatial operating position of the scan whenin these respective zones of the column. The additional signal outputsP1, Pw. and P15 of the subcolumn counter' 68 locate the spatialoperating position ot the scan with respect to the reference mark '56 onthe tape, such that other functions can be performed during these Pcounts of each cycle of the subcolunin counter, as will be set forth indetail later on in the description.

The column counter 89 is advanced once each cycle of the subcolumncounter 68, at the same time the latter resets to count P1. to countthrough eight successive counts K4 to Kg, respectively, indicative ofthe scanning periods of the columns #l to #S in a row. The columncounter is also provided with initial reset states KS and KR, indicativeor". periods prior to scanning of the columns of the tape. State KSdefines the yperiod during which the pair of apertures 22f and 22k, nextto scan the image, are still behind the shroud 24; and state KR denesthe period from the instant these apertures pass from behind the shroudinto the area of the window 23, and up to the beginning of the area outhe tape allotted to column #1.

Referring again to iFlG. 3, a description of the circuits in FIG. l willbe continued by following the operation as the character or column areasare scanned. lt should be assumed that the scanning sweeps of the imageprojected from the tape, by the pairs of moving adjacent apertures 22rand 22h of optical detector 10, have progrossed to the sweep indicated,generally in FIG. 3, by horizontal paths 83 and 89, respectively. Itshould be noted at this point that only the information produced by thescan of apertures 22! are used prior to the read scan for a character,hence, only the scan along path 88 is oi interest at this time. As thescanning progresses along path S8 from right to left across the tape,signals on output T are produced by the detector 10 in response to thesignilicant changes in the intensity of the projected light from thearea of the tape being scanned.

The iirst abrupt change in intensity of the light is detectcd as anaperture 225 in the rotating drum 20 moves upward from behind the bottomedge 92 of the window 23 in shroud 24. Signal output TS produced inphotosensitive clement 3th' by this abrupt change in intensity of lightis coupled to an and gate 84 provided at the input of the column counterSi). Prior to this time, the column counter 80 is in its idle state.providing an output signal KS, which signal is also coupled to the andgate 84. The output signal T combined with "1, KS produces a signal onthe output of gate 84 which passes through an input or gate 86 ol` thecolumn counter 80, whereupon the column counter is advanced t0 state KR.

As the scanning progresses `further along path 88 across the tape, thereference mark 46 is next detected through the same moving aperture221', and an output: signal T11 is produced. Signal output KR of thecolumn counter 80 now combines with signal TR in an and" gate 70 toprovide a signal `which passes through or" gate 74 to input g1 offlip-Hop G1, triggering this flip-flop into its true state. The outputG1 of. this ilip-liop is coupled to the clock setting circ-uit 60 toinitiate its operation. The clock signals Cs, provided on the output otthe setting circuit 60, are coupled through igate 66 to the input ol'siubcoliumn counter 68 to advance the count.

During the period 'defined by signal KS of column counter 80, and aintigate 94 connects the output sig nal TS produced in the detector 1d,into an input of the subcolumn counter 68, to reset this counter tocount P13. Referring momentarily to FIG. 3, it will be noted that counitP13 corresponds to the area allotted to the centerline of the referencemark 46. After being reset to count P13, the subcolumn counter 63 isresponsive to the next five clock signals Cs to advance to count P111.On the next clock signal CS, the subcolumn counter resets to count P1ot' a new cycle, and the column counter S0 is advanced to count K1,indicating that column of the tape is next to be scanned.

As the scan indicated by path S8 progresses across column #l of thetape, it should be noted that the character 2 printed thereon is nottraversed by the scan and the subeolumn counter 68 merely advances onsuccessive clock signals Cs to count P18 to complete the counting cyclefor the column. The subcoiumn counter 68 then begins a new cycle on thenext clock signal by resetting to count P1 and the column counteradvances to count KZ, indicative of scanning column #2.

As the scan progresses transversely across column #2 of ithe tape 12,the scan along path till 'lor the iirst time crosses a character marl;in zone ll, during signal period count P2. The optical detector ttl isresponsive to `the mark in the zone U to produce. via peak detectorcircuits 32, an output signal TC which is coupled to the true triggeriinput a1 of flip-flop A1, triggering the dipop into its true state. Itshould be noted that liipllop A1 was triggered into its ifalse state atP11 of the previous cycle of the subcolumn counter.

As the scan along path 88 continues to advance to the left in column #2,the optical detector 1d senses the mark in zone W of the character 4.This second output signal TC produced by the light passing throughaperture 22t of the detector 10' during this particular scan of column#2 is coupled from the peak detector circuits 32 to the true triggerinput a1 of the flip-tldp Al.. Since the flip-flop A1 has already beentriggered into the true state in response to the character mark in thesubcolumn zone U, this second output signal TC produced by the charactermark in the subeolumn zone W has no eticct on the state ot thisflip-Hop.

As the scanning continues to move to the left across column #2, alongthe path 83, the count of the subcolumn counter continues to advancethrough counts P11 to P111 for the subcolumn zones X and Y. The signalrepresenting count P11 is coupled along with signal A1 to an "ancV gate96 whose output is fed into an or gate 97 to advance a character scancounter 10ft) from its zero count S0 to its one count S1.

The signal output P17 is also coupled to an input no1 of the flip-ilopA1 to trigger the flip-Hop into its false state in preparation forsensing a character mark in the neat column, column #3 of the tape.

lt should now be clear that since `no portion of the character in column#l was traversed by the scan along path S8, no record was made of thisscan in scan counter 106. However, since the character "4 in column ft2was traversed by the scan along path 3S, the scan counter 10i) made arecord of this scan count at co. it P11. and the scan along path 3S thusbecame scan l for the character 4 in column #2.

Continuing with the operation during the cycle allotted to column #2, onthe next clock signal the subcolumn counter is advanced toits nal countP18. The signal output P18 serves to open an and gate 102. whichtransfers signals from the scan counter 100 indicative of the scan countS1 for the column #2, into a section of a scan counter memory 104. Thesection in the memory in which the character scan count is stored isselected, in this instance, by the column counter signal output K2 whichis coupled to the memory 194. The scan counter memory 104 is furtherdescribed in connection with FIG. 7.

Cn the next clock signal, the subcolumn counter 68 is reset to count P1and the column counter 80 is advanced to count K3 indicating that column#3 of the tape is next to be scanned. As the sean along path 8Scontinues across the remainder of the columns in the row of characters,the column counter is advanced at the beginning of each new cycle of thesubcolumn counter 68. lf the scan along path 88 touches a portion of thecharacter in any of these subsequent columns, the character scan counteris advanced to count S1 during P11 of the seanning of the respectivecolumn, and the information is stored in a section of the memory 104during the clock period corresponding to count P18 of the subeolumncounter 68.

At this point, it may be noted that the memory 104 for the scan counter100 is interrogated during each count P1 clock period of a cycle of thesubcolumn counter in order to reset `the scan counter 100 with the scancounts so far accumulated for each column by the previous scans. Thecolumn counter 8-0 selects the position in the memory 104 in which thescan count for column presently to be scanned, is stored, and theaccumulated scan count stored therein is transferred into the characterscan counter 100. The scan count is transferred during count P1 of thecycle from the memory 104 through a set of and" gates 103 to set thecharacter scan counter 100 at the proper count for the individual columnto be scanned in the remainder of the cycle of the subcolumn counter.

At the end of the subcolumn count for column #8, for the scan along path88, the subcolumn counter is reset to P1 to start counting a new cycleand an overllow signal from the subeolumn counter 68 is coupled to thecolumn counter 80 resetting the latter to the idle state KS.

The signal output of the column KS is coupled to the false trigger input0g1 of the flip-flop G1 to trigger this iiip-op into a false state. Theoutput signal G1 is coupled to the clock setting circuit 60 todiscontinue its operation and prepare it for setting the clock signalsagain, in accordance with the next output signal TR.

The clock signal C is blocked from passing the and gate 66 at theinstant liip-iiop G1 triggers to the false state. With the clock pulsesC blocked, the subcolumn counter is inactive and the column counterremains in its idle state K5 until the edge 92 of the shroud 24 iscrossed by the next aperture 22ac of the drum to effect the nextscanning sweep, indicated generally in FIG. 3 by the path 106. Theoutput signal T5, produced by the detector sensing edge 92 ofthe window23, causes the subcolurnn counter 66 to be again reset to count P13 viaand gate 94. This signal TS is also coupled to the and gate 84, asdescribed in the previous sean along path 88. The signal output of theand gate 84, which is coupled to the column counter 80 input, advancesthe column counter to state K11.

The next output signal TR produced in response to the output of theoptical detector as the reference mark 46 is scanned, is coupled to theflip-liep G1 to set the clock signal to coincide in phase with theoutput signal TR. The output of clock setting circuit 60 is passedthrough the gate 66 to the input of the subcolumn counter 68, advancingits count from count P13 to indicate the spatial operating position ofthe scan from the midline of the reference mark to the beginning of thecolumn #1.

As the scan along path 106 crosses over into column #1, the subcolumncounter 68 is reset to P1 for a new cycle and the column counter isadvanced from state KPN to count K1. As the scan progresses transverselyacross column #l of the tape, along the path 106, the detector 10 thistime senses a character marl; in zones V, W, and X defined by pulseperiods P5 to P13, inclusive. The output signal TC produced by thedetector lt in response to the mark is coupled to the ip-ilop A1 to setit in the true state indicating that the character in column #l has beendetected. During count P17, in combination with signal A1, the and gate96 is open, and the scan counter is advanced to count S1 since the scancount for this column #l was previously zero. During the next clockpenod, count P18 of the subcolumn counter, and cate 102 is opened totransfer the scan count S1 for column #l into the section of the memoryreserved for this scan count, as selected by count K1.

On the next clock signal, the subcolumn counter is reset to count P1 andthe column counter is advanced to count K2, indicative of scanningcolumn #2. The signal output K2 of column counter 80 is coupled to thescan counter memory 104 for selecting the section of the memorycorresponding to column #2 in which the scan count from the pr'ev1ousscanning sweep along path 88 has been stored. The signal output P1 fromthe subcolumn counter opens an and gate 108 to transfer the scan countS1, the scan count stored in the memory for column #2, into thecharacter scan counter 100.

As the scan progresses past the character marl: in zone 1] of column #2,an output signal TC is produced which is `coupled `to the true triggerinput n1 of the llip-op A1. As the scan continues, it also interceptsthe character mark in Zone W and another output signal TC is producedwhich is also coupled to the true trigger input (i1 of flip-liep A1.However, since the flip-flop A1 has been set in its true state by theprevious output signal T the second pulse has no effec The scancontinues to advance across the tape without detecting other charactermarks in column #2. At count P17, the true state of the A1 flip-flopindicates that the scan along path 106 transversed the character atleast once during the current scanning sweep and hence the scan counteris advanced to count S2. The Hip-flop A1 is triggered into its falsestate at P17 time s-o as to be in the proper state to indicate whetheror not a character in column #3 is traversed by the scan in the currentscanning sweep during the next cycle or" the sub-column counter.

In the next clock period, P111, of this scan in column #2, `the scancount S2 is stored in the section of the memory reserved for the scancount of column #2, WhiCh section is selected by the signal output K2.

As in the previous scanning sweep, tl remainder f the character' areasor columns in the IOW are Scanned along the path 106, and a record istransferred to the memory 104 indicative of the respective scan counts.After the scan advances past the last column, column .#8, the columncounter is advanced to its idle state KS and the signal KS triggers theflip-flop G1 to its false state, blocking the input ot cioclc signals C5t0 the SubCOlUHlH counter.

On the next scanning sweep, indicated by the path 110 in FIG. 3, anoutput signal Tg is produced, as before, by the detector upon scanningthe edge 92 of the shroud 24. The output signal TS, coupled to columncounter 10 through the `gate S4, advances the column counter to thecount K12.

As in the previous scannin sweeps, the reference mark '15 is detected asthe scan advances across the tape, and clock signal CS is set tocoincide with the output signal T11, and the subcolumn counter, whichhas been reset to count P13. is advanced on to the end of its cycle.

Upon resetting the subcolumn counter to count P1, the column counter isadvanced to count K1, indicative of scanning column #1. Also, duringcount P1 the scan count S1, for column #l stored in memory 104, istransferred. via gate 10S, to the scan counter 100. During the Scanningoi' column #l along path 110, the llipllop Ai is triggered into its truestate in response to an output signal produced by the detector inscanning the character marks. At count P17, for column #1, the characterscan counter 1.530, in recognition of the true state ol llip-ilop A1, isadvanced to count S2. ln the subsequent count, P12, the count S2 isstored in the memory 104.

During scanning in column ,2, along path 110, the scan count S2 istransferred to the scan ,ounter 100 during time P1. When character marksare detected along the scan, as shown in PIG. 3, the flip-flop A1 istriggered into its true state. At count P17, the signal output S2 fromthe scan counter serves to open the and gate 112 to permit the signaloutput P17 to pass through an "or" gate 114 1o t'nc input f1 of theflip-Flop F1. The tlip-llop F1 is triggered into its true stateproviding a true output signal F1, which signal, as will be clearlyexplained in the subsequent description, is evidence that thc next scanof this particular character is the "read" scan.

Continuing with `t'ne scan in column #2, as in the previoi "am, the truesignal output A1 of the ilip-llop Al, indre ing the character wastraversed, is coupled to the character' scan counter 100 to advance,during count P17, tht scan count to S2; and in the next clock periodP12, the scan count S3 is stored in the memory 104. In addition tostoring the scan count, the F1 signal, indicative of the true state ofthe flip-tldp F1, is stored via the and gate 102 during count P18 in thescan counter memory 104. After the remainder of the columns are scanned,and the sean counts for the respective columns stored in the memory, thecolumn counter S0 is advanced to KS.

Gn the next scanning sweep of the row of characters by the followingpair of apertures 221, and 22h, which scanning sweep is generally alongthe respective paths 116 and 117, the edge 92 of the shroud 24 isdetected, as before, through aperture 22f, and the column counter isadvanced, via gates S4 and S6, to state KR, in which state it isawaiting the detection of the reference marl-1 46 of the row. Upondetection of the reference marl; 46, a clock signal is set to coincidewith the output signal TR and the subsequent clock signals Cs areapplied to the subcolurnn counter through the and gate 66. As inprevious scanning cycles, the subcolumn counter has been reset so as toadvance from count P13, which is the spatial position with respect totime of the midline of the reference mark a5. Upon thc scan enteringcolumn #l along path 116, the subcolurnn counter is reset to count P1while the column counter advances from state KR to state K1. During thefirst signal period, count P1 of column #1, the scan count S2 for column#l is read out of the memory and routed to the character scan counter100 through the gate 108, setting the scan counter to the previous scancount S2 for column #1. As the scan progresses across the vertical zonesof the column #1, it again crosses character marks to set the llip-op A1into `its true state. At count P17, the signal output S2 opens the andgate 112 to pass the signal output P17 to the input f1 of ilip-llop F1triggering the dip-liep P1 into its true state. The character scancounter is advanced to count S3 and the flip-Hop A1 is returned to itsfalse state during the next signal period, count P17. During the timeeriod P111, the character' scan count S3 for column tll and the F1signal indicative of the true state sicarios 1l of the F1 flip-flop,stored in the scan counter memory 104.

The continuation of the scan along path 116 into column #2 is the readscan for column #2, i.e., the time during which the transverse positionof character marks in top and bottom portions of the character asscanned by both apertures 22! and 22h of detector 10 are detected andstored in the top register 120 and the bottom register 122 in twotive-digit codes, respectively, representing the character.Consequently, the character marks in path 116 are scanned by aperture22t and the character marks in path 117 are scanned by aperture 22bduring this read scan.

On entering column #2, the subcolurnn counter 68 is reset to count P1and the column counter 8G is advanced to count K2 indicative of scanningcolumn #2. The output signal P1 is coupled to the and gate 108 totransfer the scan count S3 for column #2 from the memory to the scancounter, and to reset the flip-flop F1 to its true state, as stored inthe memory in the previous scanning sweep of column, #2.

The output signal F1 opens and gates 124 and 126 which are conectcd tothe respective inputs of top register 120 and bottom. register 122. Thesignal F1 is also coupled to open the and" gate 128:1 to pass the signalP1 through an or gate 130 to the `false trigger input, 0g1, of flip-flopG1. With ip-ilop G1 in a false state, the gate 66 feeding clock signalsC3 to the `subcolumn counter is blocked, and the dock setting circuit 60is prepared for resetting in response to a new output signal TC or BCapplied on an input "or gate 132, which connects via and gate 134 and/orgate 74 to the true trigger input g1 ofthe tlip-tlop G1.

During a read scan for a character, in order to compensate for possiblehorizontal misregistration of a character in a column and synchronizethe timing of spatial position of the character marks precisely withintheir allotted zones of the column, the clock setting circuit is set forthe read scan of each character to the iirst character mark `vhich isdetected by either the top or the bottom read scan. As the scan, alongpath 116, progresses across column #2, with the subcolumn counter nolonger receiving clock signals CS, both top and bottom scans interceptthe character mark in the zone U.

It should be noted (FIG. 4) that all characters are stylized to have acharacter mark in at least either the top or `bottom portions of the Uzone. These output signals TC and BC are coupled to the true triggerinput g1 of the flip-flop G1 through the or gate 132, and the and gate134, opened by the read scan indicating signal F1, and nally the or gate74. In this manner, the output signals TC and BC trigger the ip-tiop G1into its true state to provide a signal output G1 which is coupled tothe clock setting circuit to set the phase of the clock signalscoincident with either of the output signal TC and BC, whichever happensto be present.

The signal output G1 is also effective to pass the clock signals Csthrough the gate 66, to again permit the subcolumn counter 68 toadvance. During the cycle of the tubcolumn counter that the read scanoccurs, the subcolumn counter, upon being inactivated at P1, is reset toco-unt P3 by signals F1 and P1 applied on and gate 138. In the foregoingmanner, the signal TC or BC as sensed by a character mark in the U zone,is utilized to trigger Hip-Hop G1 into a true state to initiate theclock setting circuit 60 to advance the subscolumn counter from its P3count. In this way, the centerline of the character mark in the zone Uis synchronized with the P3 count irrespective of whether or not thecharacter mark in the U zone is accurately positioned with respect tothe reference mark 46.

As shown in FIG. l, the output signals TC and BC, after passing throughand gates 124 and 126, as opened by signal F1, are coupled to the topland bottom registers 120 and 122, through individual and" gates 127 and12S, respectively. Initially, the top and bottom registers, each ofwhich has ve storage sections, as shown, are reset to store digits Othroughout. The count signals PU, PV, PW, PX, and Py of the subcolumncounter 68 are coupled to successively open gates 127 and 128 of therespective bit storage sections ol the top and bottom registers tolocate and route signals TC and BC into respective bit storage sectionsof these registers, changing each sections when a signal is present tostore a digit l." Thus, a first section in each of the top and bottomregisters is selected by the signal P11 to store the respectiveinformation signals TC and BC detected in the U zone of the characterbeing scanned; a second section in each of these registers is selectedby the signal Pv to store the 'vc infornmiion s' s TC and BC detected inthc J ci the character h ng scanned; and remaining sections in each ofthe registers are selected by the signals PW, PX. and PY to store therespective signals TC and BC detected in the respective W, X, and Yzones of the character.

In the scanning of the character 4, shown in FIG. 3, during the readscan, the TC and BC signals, detected by transversing zone U of thecharacter, are stored during signal IU as binary digits "l in respectivefirst sections of the top and bottom registers. No signals TC and TB aredetected upon traversing zone V and hence, the second sections of thetop and bottom registers during signals PV remain unchanged, indicativeof storing binary digits "0." Upon traversing zone W, only a signal TCis produced, and hence, the third section of the top register duringsignal PW is provided with a binary digit "1, while the third section ofthe botto-m register is left with a binary digit G stored therein. Upontraversing zones X and Y, no signals TC and BC are produced and hence,the fourth and lifth sections of each of the top and bottom registersare left with binary digits0 stored therein. Thus, as a result of theread scan of character "4, the top register is storing the tive-bitbinary code 00101, and the bottom register is storing the iive-bitbinary code 0000i.

Continuing with the read scan cycle for column #2. on count P17, thecharacter scan counter is advanced to scan count S4 by application ofthe signal output P11 to the scan counter input through gate 96. Inaddition, the signal P11 is applied to the flip-hops A1 and F1 totrigger them into their false state. The false trigger' input f1 of thellip-ilop F1 is connected to the output of an anc gate 140 opened to P11by the signal F1. During the following clock pcniod, count P13, the scancount S1 is stored in the memory.

During `this count P13, of the read scan, as evidenced by scan count S1,the coded information stored in each of the respective sections of thetop and 1nottom registers 123 and 122, respectively, can be routed forstorage into a butler register (not shown) for subsequent use in a dataprocessor. Or as shown in FIG. l, the information in the sections of theregisters `12|) and 122 can bc simultaneously fed, along with signalsP13 and S1 into a decoder 142, which decodes the information such thatthe appropriate one of the output leads 109 from the decoder has asignal thereon indicative of the character read, in this instance thecharacter "4.

In order to identify the character read with the column of the tape inwhich it is printed, the output leads 109 may be connected in parallelto eight sets of and" gates 10S. Each set of `these gates is connectedto be opened by a respective one ofthe signals K1 to K8, to provide forthe respective columns a signal indicative of the charac- `ter read.Thus, in this instance. the character 4 is fed ont of one gate of theset of gates opened by signal K3. Visual indicators 103, may be providedat the output of each set of gates 10S to visually display thecharacters read in the same sequential location they have on `the row ofthe tape. After the character 4" in column it?. is read out, the scancontinues along paths 116 und 117 of the remaining channels of the row,resulting in arcanos 13 merely advancing the scan count or in readingout a character, dependent on the number of scans so ier detected foreach character.

On the rfollowing scanning sweep, indicated by the paths 118 and 119,the column counter 80 is advanced to the state KR from the idle stateKS, in the same manner as in previous sweeps, to prepare for scanningpast the reference mark. As described supra, the clock signais `are setin phrase to the output signal TR and the subcolumn counter is reset toP13. As the scanning proceeds into the character area of column #1, thesubcelumn counter is reset to count P1 and the column counter isadvanced to count K1. The sequence of operations, from this pointforward in the read scan of column #1, is similar to the read scan forcolumn #2. Thus, during Athe first clock period, count P1 of column #1,the clock signals are blocked at the gate 66, as the llip-tlop G1 istriggered into its false state, and the subcolumn counter is reset toP3. Furthermore, during P1, the scan counter 100 is set with theinformation stored in the memory for column #1, ic., scan S3; and theflip-flop F1 is set to a tru-e state in accordance with informationstored in the memory. Continuing with the progress of operations, duringthe read scan of column #1, as the bottom scan along path 119 interceptsa character mark forming a portion of a character "2" in zone U ofcolumn #1, an output signal BC is produced which is coupled to thellip-ilop G1 to trigger it into its true state. The signal G1 theninitiates the operation of the clock setting circuit 60 to reset theclock signals. The information signal BC is coupled to the bottomregister 122 in a section or position selected by the signal PU, causinga binary digit l to be stored therein. Since no T C signal is present,the position in the top register 120 selected by signal PV is left inits initial state with a binary digit stored therein.

As the scan crosses into zone V, the top scan intercepts the charactermark forming the upper portion of the character 2, and the bottom scansimultaneously passes over an area in zone V which does not contain acharacter mark. The signal TC produced by the circuit 32 in response tothe character mark in the top portion of zone V is coupled to the topregister 120 through the gate 124. The position in the top registercorresponding to zone V is selected by the signal Pv of the subcolumncounter, and is changed to indicate a binary digit 1. Since the lower orbottom scart did not intercept a character mark in zone V, there was nosignal BC and the state of the selected position in the bottom registeris left storing a binary digit The scan next passes through the verticalzone W without intercepting a character mark. The output signal PW ofthe sub-column counter is coupled to the top and bottom registers toselect positions in the register for any information output signal To orBC of the detector. However, since no signals are produced in zone W,the positions corresponding to this zone in the registers are leftstoring a binary digit 0. The simultaneous scanning next advances tovertical zone X wherein both top and bottom scans intercept `charactermarks. The information signals Tc and BC, produced by the detector inresponse to the character marks are stored as binary digits "1 in thetop and bottom registers, respectively, in positions selected by thesignal output PX. The scan next crosses into vertical zone Y and sinceno character marks are present in Ythis zone, the correspondingpositions selectcd by count PY in the top and bottom registers 120 and122 are not changed in state, remaining with binary digits 0 storedtherein. During the following clock pulse period, count P17, theflip-flop F1 is triggered into its false state by signa] P17 which ispassed by the and gate 140 opened by the signal F1. Thus, during theread scan of column #1, the position of character marks in therespective zones of the column, as traversed by the read scan, aredetected, translated and stored 14 in the top and bottom registers 120and 122 according to their positions to provide two live-digit binarycodes 01010 and 0100.1, respectively, representing the character 2.

The signal P17 is passed through the gate 96, opened by the output A1,to the input of the scan counter to advance the count therein to countS4. The signal P17, is also coupled to the input a1 of the flip-flop A1to reset it into its false state to prepare for triggering by signals TCduring the scanning of the following column.

During the next clock period, which represents the last clock period ofthe read scan, the signal P18 along with signal S1 is coupled to decoder142 to decode the two live-digit ybinary codes representing thecharacter, as stored in the top and bottom registers 120 and 122,respcctively. The decoder 142, as previously described, provides asignal on one of the output lines 109 which corresponds to `thecharacter decoded, in this instance the character 2. As previouslydescribed, the character 2 for column #l can be gated by signal K1 to bedisplayed by visual indicator 103, as shown. During this same clockperiod, P18, `gate 102 is opened to pass the character scan count S4 forcolumn #l into the scan counter memory 104.

As the yscan enters column #2, the subcolumn counter is recycle-d t0count P1 and, `as in previous cycles, a carry signal is provided which:is coupled to the column counter 30 to `advance the count to K2. Whilescanning the tape 'in column #2 during the first clock signal period,P1, the count stored in `the scan counter memory 104 is transfcrred tothe scan counter through the gate 108 to set the scan counter to countS1. Thereafter, the lscan enters the zone U, interccpting the charactermark simultaneously with `both top and 'bottom portions of the scan. Theoutput signal TC, produced by the detector 10 in response to thecharacter mark, is coupled to the true trigger input a1 of the A1ip-tlop, triggering the A1 p-iiop into its true state to provide anoutput signal A1. The scanning continues across the remainder of thecolumn #2 and on count P17 of the subcolumn counter, the character scancounter is `advanced by the output signal A1, opening and gate 96 whichpasses a signal through the or gate 97 to advance the scan count to S5.Ori count P18, this scan count S5 is stored in `the scan count memory104.

lt should be noted that to ensure counting the scans after the first twoscans of `a character have been recorded, an and gate 98 is providedwhich passes a signal at count P17 if any of the signals S2 to S12 arepresent. in other words, after scan S2 has been recorded for acharacter, leven if a mark is not observed, the scan count is advanced.In the preferred arrangement, the scanning of the row of characters onthe tape is repeated as above until cach character arca is scannedtwelve times. After the twelfth scan, S12, the scan counter is recycledto S0.

On scanning sweeps between rows of the tape, the column counter isadvanced `to state KR by the output of the and gate 84 which responds tosignals TS and KS. In addition to advancing `the column counter to stateKR, the output of gate 84 actuates a multivibrator D1. The multivibratorD1 is a "one shot which is normally in a false state with the output D1'therefrom having a signal thereon. When the multivibrator is triggeredinto a true state by the output of gate 84, it will remain there for `afixed period of time, and then automatically return to its false state.The output D1 is connected into an and gate 152 along with signal KR. Asignal from gate 152 is effective t0 reset the column counter back 10KS.

The minimum time interval provided for the delay in :multivibrator D1 isthe maximum time required for the reference mark 46 to be detected if itis in the path of the scan. For example, the time delay provided forrcturning the multivibrator D1 to its false state, in the preferredarrangement, is a time interval equal to the time allotted to scanning acolumn, i.e., 18 clock periods.

During the operation of the multivibrator D1, in the event a referencemark TR is not detected in the path of the top scan, Le., the scanning`sweep is between rows, the column counter will `remain in state KR.After the delay period of the one shot multivibrator D1, its outputsignal D1 along `with signal KR provides an output signal from the andgate 152, which operates to reset the column counter back to the stateKS in preparation for `he following scanning sweep of the tape.Therefore, if the column counter is still in state KR at the end of thetime interval of the built-in delay of the multivibrator D1, theautomatic restoring of the multivibrator D1 to its false state causesthe column counter to be reset to the KS state. If no provision `weremade for resetting the column counter to the KS state, in the absence ofthe sensing of a reference mark, any mark or imperfection anywhere inthe scan `along the row of the tape could be erroneously detected as areference mark, and advance the column counter to count K1. In the eventthat no improper mark or imperfection were present on the tape, theleading edge of the shroud, on the next scanning sweep, mighterroneously actuate the circuitry in the same manner as la referencemark, causing the circuits to operate with incorrect timing.

In discussion of the tread scan, it was noted that each character isdistinguished by its pattern of character information or marks in thetop or bottom scan portions of the vertical zones U, V, W, X, and Yallotted to the character arca on the tape. Further, the scaninformation is translated into the form of two tive-digit binary codesrepresenting the characters. In FIG. 6, the live coded aones areillustrated for the character 2. The top read scan area of the Zones andthe `bottom read scan arca of the zones, respectively, define the extentof variation that the path of the top and bottom apertures ZZI and 22hcould have across the character, and still produce the desireddistinguishing signals TC and BC in the respective outputs iof thedetector circuit, so that these signals can be stored in the top andbottom registers 120 and 121, respectively, in accordance with the countsignals PU, PV, PW, PX, and Py, to provide the two five-bit hinary codesshown adjacent the output signals TC and BC, in FlG. 6.

The permissible top and bottom read scan areas include a substantialportion of the top and bottom halves of the characters. In `view of the`ample tolerances provided, it is immaterial to the reading of acharacter whether or not a scan, in which `only a fragment of the uppertip of the character is detected, is counted as the first scan, sincethe position of the read scan (the fourth counted scan) can vary in thetop and bottom halves of the characier without afecting `the accuracy ofreading the character. Further, by providing an ample tolerance for theread" scan, the reading of a character is not seriously affected `byslight variations in the normally constant speed of the tape hy the tapehandling mechanism, vari"- tions in over-all heights of the charactersdue to the weight of `the marks or lines forming the characters,vibrations and irregularities in the speed of the scanning drum, orminor variations in the Size and spacing of the scanning apertures.

ln FIG. 4, typical digit characters tl through 9" and alphabeticalcharacters 3, F, M," and T which are stylized to ibe read by theapparatus of the present invention are shown along iwith thecorresponding top and bottom five-digit binary codes representing thecharacters respectively. Each character is shown divided into the fivevertical zones U, V, W, X, `and Y in which character information, in theform of vertical segments or lines used in forming the character, ispositioned. The horizontal paths designated rt and rb passing throughtop and bottom halves of the charac-ter, respectively, such as character"O," indicate the location of typical top and liottom sensory traverses`which would intercept segments of the character to provide thecharacter information in the form of pulse position modulated signalswhich are necessary to translate the character. It should be clear fromFIG. 4, that the characters are stylized such that a portion of thevertical lines or segments forming the character is positioned in atleast the top or bottom transverse areas olVv Zone U for the rea scan ofeach of the characters. Preferably, as shown in FIG. 4, the top verticalline segments of the character are not disposed in adjacent verticalzones and the bottom vertical line scgments are not disposed in adjacentvertical zones. The groups olr signals derived from the individualsensory traverses of the segments of the character in top and bottomtransverse areas individual to each character are pulse positionmodulated signals or pulse time modulated signais representingrespective characters. The leading edge, Le., the line segment of `acharacter which is intercepted first by a sensory traverse during a readscan, provides the time reference for the position modulated signals forthe character and the signals are positioned in time relative to thetime reference to provide the position modulated signals representingindividual characters.

In FlG. 5ft, a typical character image mark or line segment 16@ is shownalong `with corresponding waveforms produced `within the detectorcircuits 32 `to provide a typical signal Tc. Upon the scanning of avertical line portion of a character represented by mark hy the opticaldetector, the photosensitive element 301, for example, provides a signalwaveform 162. This signal waveform is coupled to the input of peakdetector circuit 32. As shown in FlG. 5d, the peak detector circuitincludes `an amplifier 15S which ampliiics the input waveform 162 andadjusts its clipping level to eliminate noise, as shown hy the signalwaveform l64. The signal `waveform 164 is then differentiated indifferentiating lcircuit 156 to provide a signal `waveform 166. Thenegative-going portion of the signal waveform 166 is next amplified inamplifier 157 and t'ien coupled to the input of a blocking oscillator158, wherein the signal is reformed from the negative side of the baseline crossing, as shown in FIG. 5u, to produce the output signal Tc.

In FIG. 5b, typical printed marks or lines are illustrnted which formcharacters in the ordinary process of printing. A single, heavy line 168is detected by the detector circuits to produce a signal ivifaveform 170which is coupled to the peak detector circuits to produce adifferentiated waveform 172 andan output signal 174. A pair of characterlines 176 are shown as heavy and spaced relatively close and hence,because of their spacing, upon detection they produce a slightlydistorted signal waveform 17S. This signal waveform 17S, whendiierentiated, produces a typical signal waveform 130. This latterwaveform is amplied and reformed to produce a pair of output signals132. Thus, by means ofthe peak detection circuit 32, clearlydistinguishable output signals are produced in response to closelyspaced, heavily inked lines.

A lightly inked character image line 184 is shown along withcorresponding waveforms produced in the detector circuits. Although thesignal waveform 186 is lower in amplitude than signal waveforms 170 and17S, the output signal 188 is of the same amplitude as output signals174 and 182. Thus, the detector circuit provides uniform characterinformation output signals for translation in the translator circuits.

`In FIG. 5c, varying width character image lines 190, 192, and 194 areshown being scanned by the same size aperture 221* provided in thescanning drum. As the aperture, such as the aperture Z2t, passes lightfrom an image of character line 190, a signal waveform 198 is producedin the detector circuits. Since the aperture ZZt is narrower than thetransverse dimension of the character line 190, the signal output of thephotosensitive clement 301 detecting the light variations tends tofiattcn out on top during the time interval the aperture is completelyoccupied by the light forming the character image. However, due to thedarker inking in the middle of the character line, a gradual peaking isobserved.

The same sized aperture 22: upon scanning the narrow character Vline 192will produce an output in the detector circuits which reaches a certainlevel and tends to Batten out for the time interval all of the apertureis receiving light reected from the image 192. `Some ink will darken thearea immediately adjacent the narrow line which will produce the gradualpeaking of the output signal 200, The next character mark 194 scanned bythe aperture 22! is substantially the same `Width as the aperture, and,since the aperture is completely occupied by the light from thecharacter mark for only an instant, the signal waveform 202 is producedby the photocells and coupled from the output to the peak detectorcircuit 32. The width of the character mark i194 is the average width ofcharacter marks or lines produced in the ordinary course of printingjournal tapes, with a particular type, In the preferred arrangement,therefore, the size of the aperture, that is, the transverse dimension,is preferably designed to be the average width of the vertical printedlines produced by the particular character type. In this manner, theoutput signal of the detector is readily shaped by peak detector circuit32 to provide suitable output signals TC or Bc.

It should be noted that the scanning aperture 22t is made `to besufficiently large in size such that if imperfections or undesirablemarkings on the paper tape, not representative of reference or characterlines, should be detected while scanning the image projected from thepaper tape, the signals resulting from these spurious marks representsuch a small percentage of output signal produced by the total areaviewed through the aperture that the noise introduced thereby in theoutput signal is negligible.

Before describing the detail arrangement of the clock setting circuit 60shown in FIG. 8, the details of an adjustable delay circuit, such as thecircuit 205 shown in block form in FIG. 8, will be presented. As shownin FIG. 9, this circuit includes a multi-apertured core 250 having ahigh residual magnetism and a substantially rectangular hysteresischaracteristic. The core 250 is provided with a major aperture 254 and aminor aperture 259. A clear signal winding 251 and a set signal Winding252 are `wound about a leg of the major aperture 254, and an inputsignal winding 256 and a reset signal winding 257 are wound about a legof the minor aperture 259. Connected to reset signal winding 257 is areset circuit 260. Connected to one end of input winding 256 is a signalinput 261 and connected to the other end oi winding 256 is a signaloutput 262. ln the operation of the delay circuit 205, a low potentiallevel signal applied to the clear input 263 of winding 251 initiallysaturates the entire core in one direction. A low potential level setsignal applied to the set input 264 of winding 252 serves to partiallyreverse the flux about the path otn the major aperture 254 and tothereby store in the path about the minor aperture 259 a predeterminedamount of ilux which controls the delay of the circuit. It should benoted that during the period the delay circuit is inactive, the signaloutput 262 is of a low operating potential level (-4 v.) and signalinput 261 is at a high operating potential level (O v.). When thesignal, applied on the signal input 261 swings to the relatively lowpotential level, the current applied to the input signal winding 256reverses magnetic flux previously stored around the small aperture 259by the set signal, and during the reversal only a small current passesthrough winding 256 to the 50 v. source. When the reversal is completedthe sudden drop in impedance creates a sharp increase in current passingto the -50 v. source. Thus. the effect of this operation is that thenegative-going leading edge of the signal on input 261 is delayed inappearing as a positive-going leading edge on the output 262 for a timeinterval which is dependent upon the amount of the magnetic fluxreversal in the path around the minor aperture. Thus, it is only whenall the flux about aperture 259 has been reversed that the signal on theoutput 262 becomes relatively high in potential level. This signal onthe output 262 is held at the high potential level by the low potentialsignal on the input 261. The reset circuit 260 which includes the resetwinding 257, is eiiective, after the signal on input 261 is no longerlow in potential level, to cause magnetic llux of the same magnitude asthe set signal to be reset in the path about the minor aperture 259. Thetime required to reset the stored ux is equal to the delay of thecircuit. The reset circuit 260 is also connected to maintain conductionthrough transistor 266 while reset signal 265l is present. ln this way,the trailing edge of the signal on the output 262 is delayed for thesame time interval as the leading edge Was delayed.

In a similar manner, all subsequent signals coupled to the input 261 ofthe delay circuit are delayed for the time interval determined by theset signal until a clear signal is applied to the circuit. For a moredetailed dcscription of the adjustable delay circuit of the typedescribed, reference is made to a co-pending US. application of RichardK. Gerlach et al., Serial No. 828,910, iiled luly 22, 1959. u

As noted previously, the clock setting crctut 60 operates to synchronizethe timing lof the clock signals C with respect to the timing of asignal, such as signal TR, produced by detecting the reference mark 46on the tape. This clock setting circuit ioperates at the occurrence of aTR signal to delay each of the successive clock signals C by a delaytime interval determined by the phase difference between thenegative-going edge of a C or C signal and the leading edge of a TRsignal.

As shown in FIG. 8a, a clock pulse C, provided by the reading head 37,is shaped as a square wave, i.e.,vto periodically swing between arelatively high operating potential level and relatively low operatingpotential level. As shown in FIG. 8, this signal is amplified inampliler 217 and inverted in inverter 208 to form on separate leads therespective signals C and C which signals are complements `of each other,i.e., when signal C is at the high potential level, signal C' is at thelow potential level, and vice versa.

AS previously described in connection with FIG. l, and as illustrated inFIG. 8a, signal TR, produced by detector 10, operates to triggerflip-flop G1 into a true state. During the time period the flip-llop G1is in the true state, its output G, is at the high potential level andits output G1' is at the low potential level. Thus, the routputs fromthe G1 llip-ilop rather than the TR signal, are directed into the clocksetting circuit 60 to set into this circuit a desired amount of delay,and thus initiate its operation.

As shown in FIG. 8, the G1 and C signals are fed through an or gate 214whose output is connected tn the set input 264 for the iirst delaycircuit 205. As will be more clearly understood infra, this output fromthe or gate 214 also provides the clear input signal for a second delaycircuit 206. In a similar manner, the G1 and C' signals are fed throughan or gate 222 whose output is connected to the clear input 263 for thefirst delay 205 circuit and the set input for the second delay circuit206.

Referring to the rst delay circuit 205, when the llipflop G1 is in itsfalse state, prior to receipt of the TR signal on its true trigger inputg1, clock signals C are applied to the set input of the rst delaycircuit 205, and clock signals C' are applied to the clear input of thisfirst delay circuit 205. The waveforms for the clock, "set and clearsignals as applied to the first delay circuit 205 are shown in FIG. 8a.For such Operation, each low potential level portion of clock signal C,as evidenced at the output of or gate 214, sets a delay into the delaycircuit 205, and the following low potential level portion of clocksignal C', as evidenced at the output of or gate 222, clears this delayfrom the circuit in preparation for setting `by a subsequent set signal.The important operation to note here is that prior to iip-op G1 being ina true state the circuit is cleared each clock signal period. For thiscondition the output from the delay circuit is of no concern since the`false State of the G1 llip-tlop prevents any signals on the output 262of delay circuit S from passing through the and gate 220.

Now then, if during the operation of the character reader of FIG. 1, theTR signal is produced, the flip-nop G1 is triggered true, as previouslydescribed. As shown in FIG. 8a, if output G1 swings to the highoperating potential level at the instant the clock signal C is at itslow potential level, the set signal 218, fed into the first delaycircuit 205 is shortened, as shown, depending on the occurrence `of thepositive-going edge 212 of the G1 signal within the period that the Csignal is at its low potential level. As a consequence of the shortenedset Signal 218, the period of delay set into the delay circuit islikewise shortened.

The clear signal input to the delay circuit 205 is now cut-off sinceoutput G1 is high in potential level and maintains the output of the iorgate 222 at the high potential level. It should be noted that theportion of the input signal waveform C, designated 210 in FIG. 8a, isapplied onto the input 261 of the delay circuit 20S simultaneously withthe `application of the set signal 218. The set signal serves to holdthe signal output 262 at the low potential level, such that theformation ot' the first output signal 211 follows the set signal 218, intime, as shown in FIG. 8a. The rst delay circuit 205 now resides in acondition in which it is set to provide a fixed interval of delay for`all subsequent clock signals C, provided at its signal input 261.

Since signal C was at its high potential level, at the time lip-flop G1was triggered true, a ip-flop Q1 is left in the false state having ahigh level signal on output Q1', as shown by the waveform Q1 in FIG. 8a.This condition assures that the output of delay circuit 205 passesthrough gate 220` to provide signals Cs. This operation prevails for anumber of clock periods until flip-flop G1 is triggered false inaccordance with the condition on the false trigger input g1 shown inFIG. l.

It should be obvious that the positive-going leading edge 212 ol thesignal G1, as shown in FIG. 8a, may occur during either the relativelylow or relatively high potential level portion of the cycle of the clocksignal C, and it is desired to set the clock setting circuit duringeither portion of its cycle. Thus, to provide a properly initiateddelayed series of clock signals during the high potential level portionot' the clock signal C, the second adjustable `delay circuit 206 isprovided in which clock signal C coupled to its signal input are thecomplements of the clock signal C. It should be noted, that clock signalC' iis at the low level potential when clock signal C is at the highlevel potential, and vice versa. As previously discussed, the set signalfor the second delay circuit 20'6 is derived from the or gate 222, andthe clear signal for the circuit 206 is derived from the or gate 214. lfthe Tpu signal triggers the G1 flip-flop into a true state during aperiod that clock signal C' is low in potential level, then a set signalpasses through the or gate 222 to set a delay into second delay circuit206 such that this delay circuit can now, in response to clock signalsC', provide the properly delayed Cs clock signals.

The adjustable delay circuits are designed to respond to low potentallevel input signals. Thus, during any particular initiation of the clocksetting circuit 60, only one of the adjustable delay circuits 205 or 206is active to provide the desired delayed clock signals CS. The delay circuit `activated is the delay circuit reciving the low potential levelclock signal C or C' at the instant the flip-ildp Gl is triggered intoits true state. Thus, at the instant signal G1 is switched to a highpotential level, a low potential level "set signal, whose duration isproportional to 7 f the desired delay, is produced either on the outputof the a 20 or gate 214 by the combination of the G1 signal with theclock signal C, or on `the output of `the or gate 222 by the combinationof the G1 signal with clock singal C.

Flip-liep Q1 has been provided to gate out che output of only the activeadjustable delay circuit. During the period that no clock signal outputCs is provided `by the setting circuits, i.e., during signal outputperiod of G1', the false state Q1 of flip-Hop Q1 follows the clocksignals C', as shown `by the respective waveforms in FIG. 8a. To triggerthe flop-flop Q1, and" gates 226 and 227 1`ndividual to the triggerinputs q1 `and q1 pass clock signals C `and C' respectively, to triggerthe ilip-llop Q1. Upon the occurrence of a singal T11, for example,which triggers the Hip-liep G1 to its true state, the gates 226 and 227no longer pass `clock pulses C and C and the ilip-op Q1 remains in thclast state.

The signal output of the `adjustable delay circuits 205 `and 206 ispassed through the and `gate 220 or `the and" gate 2216, and thenthrough `an or gate 22S to the output of the clock setting circuit.During the periods adjustable delay circuit 205 is operative to producethe desired delay, the signal outputs Q1' and G1 open gate 220 to passthe `signal output of the adjustable delay circuit 20S through the or"gate 225. During the periods that the `adjustable delay circuit 206 isoperative to produce the desired delay, the signal outputs Q1 and G1open the gate 224 to pass the signal output of adjustable delay circuit206 through or gate 225. Thus, the output from one ot `the delaycircuits, as selected iby che Q1 liip-op, provides the series of clocksignals CS which have been phased `with thc `reference signal TR.Reference is made to a copcnding U.S. application of Richard K. Gerlachet al., Serial No. 69,050, tiled November 14, 1960, which ditscloses andclaims `the clock setting circuit shown in FIGS. 8 and 8a, and describedsupra.

Reference will next be made to FlG. 1l which shows detals of the logicalcircuits which control the operation of ilip-ilops E1 to E4, inclusive,forming the character scan counter 100, and the associated Hip-flops A1and Fl, to enable these components to operate as described in connectionwith FIG. l. As shown in FIG. ll, the physical embodiment ormechanization of the logical circuits of the preferred embodiment of thepresent invention is accomplished by cores and windings. The cores arewound so as to operate in accordance with the inhibit core logicprinciple, as disclosed in a co-pending U.S. application of Kenneth O.King et al., Serial No. 817,851, filed June 3, i959.

The respective trigger logic cores of the scan counter flipilops andassociated flip-flops are shown in FIG. ll as vertically disposed slimrectangles, bearing reference numbers `as indicative `at the upper endthereof. Windings on a core are indicated `by slant lines atintersections of the core with respective selected current signal lineswhich `are shown as horizontal lines. For example, core 244 has awinding for clock signal CS (double slant line `at the intersection ofthe clock signal line and the core), a winding for bias signal Q,individual windings for each of current signals E2', E3', E4 and P17',and a sense winding connected in sense line e1 on which is `generatedthe truc trigger signal for the El Hiphop. The other cores have windingsas indicated. The directions ofthe various current signals `areindicated `by arrow points in the nespcctivc lines at the left oi core230. The convention or symbolism employed in FIG. ll is well known inthe art as the mirror notation, wherein if `tthe yslant linerepresenting a Winding were a mirror and the current in the currentlines were a beam of light traveling in the saine direction as thecurrent, the light would be reflected either upwardly (l) or downwardlyaccording to the direction of the slant line; `and the interpretation isthat if the light were thus reflected upwardly the current would tend tocoerce ithe core in the direction of the l state and if it werereflected downwardly the current would tend to coerce the core to 0. Oncurrent-carry- 2l ing windings, double slant lines indicate `a doublestrength coercive effort, 2l, and `singie slant lines ldenote a singlestrength coercive effort 1I. Thus, the ciock `signal Cs is applied witha 2l positive coercive (upward) effect and the bias (Q) continuallyexerts a negative coercive etfort of value -I tending to drive or holdthe cores to "0. Current signals, such as A1', E1, E1', etc., are termedinhibit signals. They Vare each of coercive strength 1I and areindividually applied in the negative direction to cores, as indicated.In the absence of any inhibit signals on a core, the double `strengthcoercive eflort of the clock signal Cs isablc to drive the core to 1,against the bias Q.

In accordance with the inhibit core logic principle, each logical andfunction of n Boolean equation is assigned to be mechanized by anindividual core. Thus, in FIG. 1l, the logical and function E2 E3 E4 P17of equation e1 is mechanized by core 244. In applying inhibitingcurrents to a core in order to mechanize a logical and function usingthe principles of inhibit core logic, the inverses of the signal outputsindicated in the equation are actually applied as inhibiting currents.Thus, it is noted, in FIG. il, that core 244 has windings forapplication thereto of inhibit current signal outputs E2', E3', E4' andP17 (the inverses of the signal outputs shown `by the e1 equation). FIG.lla shows a graph of the waveforms of the signals applied to core 244.The inhibit signals are all shown to be absent during the P17 period andconsequently core 244 is not inhibited and will be turned over once bythe clock signal CS and again by the bias Q at the termination of theclock signal. Thus, at the termination of the ciock signal, anegative-going signal is generated on sense line e1 which will triggerfiip-op El to a true state.

One of the operations of the scan counter provided by the cores in FiG.ll, is the ability to clean i.e., initially reset to zero each of theflip-flops El to E4. To accomplish this a clear inhibit signal isnormally continuously applied and is effective on a core 246. Senselines, connected to the false trigger inputs for each of the flip-flops,are linked by windings to this core 246. Thus, whenever the clear switchis opened, as may be done in preparation for initial operation of thecircuits, the clear inhibit signal is absent and core 246 is permittedto be turned over by the next Cs signal, causing signals to be inducedon all the sense lines to trigger all the flip-flops into a false state.

As previously discussed in connection with FIG. l, `the character scancounter 100 is able to advance through count positions S to S12.inclusive. As indicated by the table in FIG. 10, each of these countpositions is defined by a unique combination of true or false states ofthe four flip-flops E1, E2, E3 and E4- included in the scan counter.Thus, count S0 is defined by each of these iiipdiops El to E4,inclusive, being in a faise state (storing a binary digit 0); count S1is defined by Hip-flop E4 `being in a true state (storing e binary digit1), and flip-i1ops E1, E2- and E3, earch being in a faise state; andeach of the remaining counts S2 to S12 are defined as storing binarydigits as shown in the table of FIG, 1G. The trigger inputs for each ofthe flip-flops El to E4, inclusive, are mechanized to change theseHip-Hops from the states representing the existing count of the scancounter to the states representing the next following count of thecounter in response to a count signal P17 of the subcolumn counter 68.

The Boolean equations defining how each of the ipfiops El, E2, E3, andE4 must be triggered to advance the count of counter 68 are derived byreferring to the table in FIG. 10. There it is noted, that the E1 flipopis changed from a faise state to a true state on advancing from count S7to SB. An examination of the unique conditions of count S7 indicate thatthe true trigger input e1 for the El ip-tlop can be defined by equatione1=E2E3E4P17- As previously discussed in connection with FIG. ll, thecore 244 is inhibit wound with outputs E2', E3', E4', and P11 to performthis logic. The sense Winding e1 on core 244 will thus provide an outputsignal thereon to trigger ip-iiop E1 into a true state, if signals areabsent on all the inhibit windings of core 244. It is noted on movingdown the table from count S0 to S12 that the El lipflop never changesfrom a true state to a false state, and hence, no false trigger inputfor the E1 hip-flop is needed during such advance.

On examining the action of E2 flip-hop during the counting shown by thetable in FIG. 10, this flip-flop is changed to a true state uponadvancing from count S3 to Si, and again upon advancing from S11 to S12.Thus, the true trigger input e2 for the E2 flip-hop can be defined as:e2=ElE2'E3E4P17lE2E3E4P17. These VV'O lg ical and functions for equatione2 are mechanized by applying the inverses of the output currentsignals, as deiined by the equation, onto the windings of cores 240 and241. It should be noted here that the common sense line e2 passingthrough these cores logically sums the two and or product functions. Asimilar examination of the table indicates the E2 flip-flop changes froma true state to a false state upon advancing from count S, to count S8.This can be defined by the equation ofazEzEaEtP 17 which equation ismechanized by the windings on the core 243.

In a similar manner, the count trigger equations for the E3 and E4flip-flops can be derived. These equations are as follows:

The three logical and functions included in the e3 equation aremechanized by the windings on cores 2.36, 237 and 23S; and the onelogical and function in the oe3 equation is mechanized by the windingson core 239. The three logical and functions included in the e4 equationare mechanized by the windings on cores 232, 233 and 234; and the onelogical and function in the e4 equation is mechanized by the windings oncore 235.

In addition to designing the scan counter to advance from the count itis in, to the next count, as indicated by the table of FIG. l0, thecounter is designed to reset to count S0, when it is in count S12 at thePy count of a cycle of the subcolumn counter.

Thus, by examination of the table in FIG. l0, it is noted that inchanging from S12 to S0, only iiip-liops E1 and E2 need be changed to afalse state since flip-flops E3 and E4 are already false `during countS12. The reset equations are as follows:

The cores `for mechanizing those reset equations are designated byreference numerals 245 land 242 in FIG. l1.

It should be noted that the scan counter operates to `advance to S1,after `being reset to S0, only if flip-flop A1 is in a true state at P17of a scan cycle of a column. Furthermore, the scan counter will advanceto S2 only if the ilip-ilop A1 is in a true state at P17 of the nextscan cycle of this same column. If the A1 flip-flop is not set true inthe next scan cycle for the column, it is an indica- `tion that thesetting of pdiop true during the previous scan of the column was due toan erroneous mark on the tape, vfor example. Thus, instead of advancingto S2, the scan counter is designed to reset to Sn again. This isindicated by 4the and function A1E3'E4P17 included in the e3 countingequation. lf the A1 tiipdiop is set -true during two consecutive scancycles of a character, after the scan counter has been reset to S0, thescan counter will advance at P17 of consecutive scans of the 23character irrespective of the condition of the A1 flipflop.

ln addition to counting scans, the scan counter, at P18 of a cycle ofthe subcolumn counter, is provided with the ability to transfer thecontents of its ip-ops E1 to E4, inclusive, to a column of cores of thememory 104, as selected by the output of the column counter. Further,the scan counter 100 is arranged to be set, at P1 of a cycle, with datastored in a column of cores of the memory 104, as selected by the outputof the column counter 80. A portion of the circuits of the scan counterlmemory 104 is shown in FIG. 7. The memory is provided with eight columnsof cores, one corresponding to each of the columns of a tape (FIG. 2).Each column of cores includes tive cores, one corresponding to each ofthe five llip-ops E1, E2, E3, E4, and F1. The false output signals E1',E2', E3', E4' and F1 provided by `these flip-flops are respectivelyapplied on individual windings provided for cach row of cores. A write"circuit is provided for cach of the columns of cores; and `a readcircuit is provided for each of the columns of cores. The write circuitfor the tirst column of cores, shown on the left in FIG. 7, comprises acircuit from ground `through channel select transistor 270 and throughdrive line i271, which is wound on each of the first column cores, to acommon line 272, and then through timing transistor 273 to a -v. source.The drive line 271 is wound on each of the cores in a column in adirection which is reversed in direction from the direction in which thesignal lines E1', E2', etc., are wound on the respective cores of thecolumn. Thus, to write into the lirst column of cores, if signal K1 ispresent to enable transistor 270 to conduct, and signal P111 is presentto enable transistor 273 to conduct, each of the cores in the tirstcolumn will turn over unless inhibited by a signal on one of the signallines E1', E2', E3', E4', F1'. In a similar manner, when one of theother signals K2 to KB is effective, the information in the E1 to E4 andFl llip-flops will be written, at P13 time, into a selected column ofcores in the memory, by a current drive signal passing `from ground tothe -v.

source.

The read" circuit for the first column of cores comprises a circuit fromground through the channel select transistor 270 and through drive line274, which is wound on each of the first column cores, to a common line276, and then through timing transistor 275 to the -v. source. The driveline 274 is wound through the first column cores in a direction which isreversed to the direction of the windings of drive line 271. Thus, toread out of the lrst column of cores, if signal K1 is present to enabletransistor' 270 to conduct, tand if signal P1 is present to enabletransistor 275 to conduct, each of the cores `in the rst column, notalready in a zero state, will `turn over, causing signals to be providedon respective ones of the sense lines m1, m2, m3, m4 and m1, providedfor each row of cores. ln a similar manner when one of the other signalsK2 to Ka is effective, the information in the selected column of coreswill be rcad" out onto their respective sense lines. The sense lines m1,m2, m3, m4 and m1 are respectively connected to the true trigger inputlines e1, e2, e3, e4 and ef shown in FIG. 11, resulting in therespective llip-ops E1 to E4, inclusive, and F1 being set in accordancewith the data read out of the selected column of the memory.

When Writing information into the memory from the ip-ops E1 through E4and F1, during P13, it is also desired to reset these tlip-tlops to azero state. Thus, each of the false trigger input lines ue1, gez, oe3,e4 and f1 has a signal P13 applied thereon, as shown in FIG. 1l,resulting in the respective tlip-tlops being triggered to a false state.

The core 247 is provided to initially set the A1 tlipop `true inresponse to a rst character signal TC sensed by the optical detectorduring the scanning process.

In this instance, the TC signal is employed to drive the core, as shown.The sense line for this core connected to input line u1, is wound in anopposite direction to the other senso windings, so as `to enable the A1flip-flop to be triggered by the signal produced by turning over thecore with the drive TC, rather than the bias Q. As shown, a signal P17supplied to input line 0a1, provides for triggering [lip-tldp A1 l'alse.

The F1 llip-tlop is sct true when the scan counter 100 is in count asshown and described in connection with FIG. l. Thus, the true triggerinput equation iiz'g'lfifn is derived by defining count S2 in the tableof FIG. l0. This equation is mechanized by core 230 shown in FIG. ll.The F1 ipdlop is triggered false by conditions defined by equation0f1:F1P17. This is mechanized by core 231 in FIG. il.

The subcolumn counter 68 and column counter 80 shown and described inconnection with FIG. 1, have their counting and reset operationssimilarly defined by a table, such as shown in FIG. l0. Accordingly, thetrigger inputs of the flip-flops forming these counters may bemechanized by cores wound in accordance with the inhibit core logicprinciples, as discussed in detail for scan counter 100.

While the form of the invention shown and described herein is admirablyadapted to fulll the features and objects before enumerated asdesirable, it is to be understood that it is not intended to confine theinvention to the one form or embodiment disclosed herein, for it issusceptible of embodiment in various other forms without departing fromthe principle involved or sacrificing any of its advantages, and theinvention is therefore claimed in any ot its forms or embodiments allcoming `within the legitimate and valid scope of the claims whichfollow.

What is claimed is:

1. In a character reading system, means for scanning an area forlocating individual characters in order to detect line segments formingpredetermined portions of the character to produce respective groups ofposition modulated signals representing individual characters, eachcharacter being stylined to have at least lirst and second spacedportions, each portion having character segments in predeterminedposition locations; means for progressively scanning the area includingthe characters by advancing successive sensory traverses across the areain one direction to locate predetermined portions of the characters;means for sensing a leading line segment of the character by at leastone of said traverses to produce signals for locating said individualcharacters in another direction; means for detecting the line segmentsforming said predetermined portions of the character by simultaneoussensory traverses of the character to produce groups of positionmodulated signals representing respective characters in response to thesensing by the sensing means of the presence or absence of a segment ineach portion of the character; and means coupled to said lastmentionedmeans for identifying a character in response to said position modulatedsignals.

2. Apparatus for optically reading characters recorded in a row of arecord medium, which characters have been stylized so that segments oflines used in forming the character are positioned in spaced first andsecond portions of the character, each portion having character segmentsin predetermined position locations; an optical scanning means providinga pair of moving apertures for progressively scanning across the row ofcharacters; counting means coupled to said scanning means for countingthe number of times the presence of each character in the row is sensedby one of the apertures of said scanning means to determine when saidscanning means has progressed to where the pair of apertures arepositioned over the lirst and second portions of the characters', outputcircuit means responsive to said counting means and coupled to saidscanning means for producing position modulated signals in response tothe signals generated when the apertures of said scanning means scan theline segments located in the first and second portions of the character;and means coupled to said output circuit means for identifying acharacter in response to said position modulated signals.

3. Apparatus for reading characters according to claim 2 wherein thesize of each moving aperture is large relative to the size of minorvisible defects in the record medium, whereby the signal resulting fromsuch defects is such a small percentage of the signal produced whenviewing a line segment through the aperture, that the noise introducedinto the output signal thereby is negligible.

4. Apparatus for reading characters recorded in a row on a recordmedium, which characters have been stylized such that line segmentsforming the character are positioned in spaced rst and second portionsof the character, each portion having character segments inpredetermined position locations; a scanning means providing a pair ofspaced scanning elements for progressively scanning the record medium ina direction parailel to the row of characters so as to traverse saidsegments; sensing means for sensing signals generated by said scanningmeans; counting means responsive to the output of said sensing means forcounting the number of times the presence of each character in the rowis sensed by one of the scanning elements of said scanning means todetermine when said scanning means has progressed to a posi- [tion tosimultaneously scan the first and second portions of the character;output circuit means connected to the output of said sensing means forproducing position modulated signals in response to the signalsgenerated when said scanning means scans the line segments located inthe first and second portions of the character; and means coupled tosaid output circuit means for identifying a character in response tosaid position modulated signals.

5. A system for reading a row of characters printed on a record medium,which characters have been stylized such that segments f lines used informing the character are located in a plurality of predetermined pathsacross the character area, each character being stylized to have atleast first and second spaced portions, each portion having charactersegments in predetermined position locations; a scanning means forprogressively scanning `the row of characters so as to traverse saidsegments; a timing means for defining the location of each scan alongthe row of characters; counting means coupled to said scanning means forcounting the number of times the presence of each character in the rowis sensed by said scanning means to determine when said scanning meanshas progressed to a position to scan the predetermined paths of thecharacters; output circuit means coupled to said timing means and saidscanning means for producing position modulated signals corresponding tothe relative position of signals generated upon scanning the linesegments located in the predetermined paths of each of the characters ina row; and means coupled to said output circuit means for identifying acharacter in response to said position modulated signals.

6. A system for reading a row of characters recorded on a record medium,which characters have been stylized such that segments of `the linesused in forming the character are positioned in at least first andsecond predetermined portions oi' the character, each portion havingcharacter segments in predetermined position locations; scanning meansfor progressively scanning the row of characters so as to traverse saidsegments; timing means for providing outputs identifying the location ofeach scan as it moves along the row of characters; counting meanscoupled to said scanning means for counting the number of times thepresence of each character in the row is sensed by said scanning meansto determine when said scanning means has progressed to a position toscan said predetermined portions of the characters; output circuit meanscoupled to said scanning means for producing position modulated signalsin response to the signals generated when said scanning means scans theline segments located in said predetermined portions of a character;resetting means connected to said timing means and said output circuitmeans and responsive to the first signal received by said output circuitmeans to reset said timing means such that the outputs thereof identifythe relative position of the signals received by said output circuitmeans as said scanning means scans the predetermined portions of acharacter; and means coupled to said output circuit means foridentifying a character in response to said position modulated signals.

7. Apparatus for reading one or more characters recorded in a row on arecord medium, which characters have been stylized such that segments oflines used in forming the character are positioned in first and secondportions of the character, each portion having character segments inpredetermined position locations; a scanning means for progressivelyscanning the record medium in a direction parallel to the row so as totraverse said segments; counting means for counting the number of timesthe presence of each character in the row is sensed by said scanningmeans to determine when said scanning means has progressed to a positionto scan the iirst and second portions of the character; translatingmeans for translating the signals generated when said scanning meansscans the line segments located in the first and second portions of thecharacter, and for producing position modulated signals in response tothe presence or absence of a segment in each portion of said character;and means coupled to said translating means for identifying a characterin response to said position modulated signals.

8. A system for reading characters which have been stylized such thatsegments of the lines forming the character are positioned in at leasttirst and second predetermined portions of the character. each portionhaving character segments in predetermined position locations; a recordmedium on which a row of the characters and a row reference mark isprinted; scanning means for progressively scanning the row of charactersso as to traverse said segments and produce position modulated signalsin response to the presence or absence of a segment in each portion of acharacter; timing means; a resetting circuit responsive to a rowreference mari; for resetting said timing means to denne the location ofthe scan along the row of characters; counting `means connected to saidscanning means for counting the number of times the presence of eachcharacter in the row is sensed by said scanning means and providing anoutput when said scanning means has progressed to a position to scansaid predetermined portions of the characters; gating means connected tothe output of said counting means for gating out said position modulatedsignals generated by said scanning means as it scans the line segmentslocated in said predetermined portions of a character; said resettingmeans responsive to the first signal sensed as said scanning means scansthe predetermined portions of a character, to again reset said timingmeans to identify the relative positions of signals Agated out of saidgating means; and rneans coupled to said sensing means `for identifyinga character in response to said position modulated signals.

9. A system for reading a row of characters recorded on a record medium,which characters have been stylized such that segments of lines used informing the character are positioned in rst and second predeterminedportions of the character tarea, each portion having character segmentsin predetermined position locations; a scanning means for progressivelyscanning across the row of characters so as to traverse said segmentsand produce position modulated signals in response to the presence orabsence of a segment in each portion of a character; timing means forproviding outputs defining the location of the scan along the row ofcharacters; a scan counter

11. IN APPARATUS FOR OPTICALLY TRANSLATING AN ALPHANUMERIC CHARACTERFROM A RECORD MEDIUM, SAID CHARACTER BEING STYLIZED TO HAVE AT LEASTFIRST AND SECOND SPACED PORTIONS, EACH PORTION HAVING CHARACTER SEGMENTSIN PREDETERMINED POSITION LOCATIONS, OPTICAL SCANNING MEANS FOR SCANNINGSAID FIRST AND SECOND PORTIONS OF SAID CHARACTER IN A DIRECTION SO AS TOTRAVERSE SAID SEGMENTS, OPTICAL DETECTING MEANS COUPLED TO SAID OPTICALSCANNING MEANS FOR PRODUCING POSITION MODULATED OUTPUT SIGNALS INRESPONSE TO THE SENSING BY SAID SENSING MEANS OF THE PRESENCE OR ABSENCEOF A SEGMENT IN EACH POSITION OF SAID PORTIONS, MEANS FORDIFFERENTIATING SAID POSITION MODULATED SIGNALS AND FORMING THEREFROMDISCRETE PULSES, AND MEANS FOR